1. Field of the Invention
The present invention relates generally to the inventory control and identification of semiconductor chips during manufacturing and testing. Specifically, the present invention relates to an apparatus and method for the consistent and accurate placement of adhesive bar code labels on semiconductor chip processing trays.
2. State of the Art
During manufacturing and testing of semiconductor chips, processing trays are routinely used for handling large numbers of chips. Processing trays designed and built in compliance with standards propagated by the Joint Electronic Device Engineering Council (JEDEC)--commonly referred to as JEDEC trays--are widely used within the semiconductor industry. Generally, JEDEC trays consist of a grid-like, open lattice structure defining a plurality of cavities in rows and columns capable of holding a plurality of semiconductor chips in a two-dimensional array. The trays, which are usually injection molded from plastic, vary in overall dimensions and grid size, depending on the type of chip the tray is designed to hold. JEDEC trays also have surface features, such as locating and hold-down tabs, that allow the trays to be manipulated by automated handling equipment. Additionally, JEDEC trays are stackable, allowing for the simultaneous handling or storage of large numbers of semiconductor chips.
To facilitate inventory tracking and control, test lot identification, sorting and binning, and subsequent storage and shipping of semiconductor chips, manufacturers typically place some type of identification tag on each JEDEC tray. A commonly used identification tag used with JEDEC trays is an adhesive bar code label. The bar code label is typically applied to a lateral edge of the JEDEC tray, and the label allows the manufacturer or customer to identify the contents of each tray in an automated processing system by scanning the label with a bar code reader.
Numerous devices for applying adhesive labels, and similar devices for applying ink stamps, exist in the prior art. Sato et al., U.S. Pat. No. 4,436,573; Pfeffer, U.S. Pat. No. 4,369,582; and Kerr, Jr., U.S. Pat. No. 5,851,332, all disclose devices directed to the manual application of adhesive labels. Dour et al., U.S. Pat. No. 5,517,916, discloses a self-inking stamp for manually applying an ink stamp. Also, Matsuguchi, U.S. Pat. No. 4,585,505, and Franklin et al., U.S. Pat. No. 5,540,795, disclose label applying systems adaptable to automation.
Application of a bar code label to a JEDEC tray is usually accomplished by manual, hand-placement of the label to the JEDEC tray edge. However, hand-placement of a bar code label to a JEDEC tray has proven to be insufficiently accurate for use with automated manufacturing equipment. To identify the contents of a JEDEC tray, automated processing systems generally rely on the bar code reader to scan the bar code associated with each tray. The task of scanning a bar code label within an automated production line requires that the bar code be accurately and repeatably located relative to the reader. This task is frustrated by the manual application of adhesively backed bar code labels, which may result in the inconsistent and inaccurate placement of some labels upon a corresponding application surface. Thus, a need exists in the semiconductor industry for an apparatus and method directed to the application of an adhesive bar code label to a JEDEC tray that is accurate and, at the same time, repeatable.